DESCRIPTION: (Applicant's Description) The Missouri Valley Cancer Consortium (MVCC) is a multi-component community-based cancer research effort based in Omaha and Lincoln, Nebraska. The catchment area includes western Iowa and east-central Nebraska. The 1990 population was about 1.2 million. The MVCC is the third largest accruer of patients to cancer treatment protocols and the second largest to cancer control protocols in the North Central Cancer Treatment Group. The four main components of the MVCC are Alegent Health Bergan Mercy Medical Center, Alegent Health Immanuel Medical Center, Lincoln Cancer Center, and Creighton University. These institutions have had an established research program with the North Central Cancer Treatment Group (NCCTG) since 1983. Numerous investigators (52) participate and are responsible for over 3200 new cancer patients annually. Over the past 2 years of the previous funding period, these investigators have entered 201.1 and 223.4 patients on NCI-approved cancer treatment and control trials, respectively. The proposed principal and associate principal investigators of the MVCC are currently directing the conduct of the Breast Cancer Prevention Trial and the Prostate Cancer Prevention Trial (837 enrolled and 639 randomized for the state of Nebraska. Previous research base affiliations with NCCTG, ECOG, and NSABP would continue with the addition of RTOG and GOG and enable the future support of this high level of accrual as a NCI-funded CCOP.